Chipping medium. Brush a thin coat of chipping medium over initial paint coat and allow it to dry, force drying possible (low setting). Spray a 2nd coat of paint over so prepared layer of chipping medium and allow it to dry, force drying not recommended. Once dry you can start removing portions of paint using a brush soaked with water. Wet the entire paint layer. Use scrubber brush for quicker results. Use only with water-based (acrylic) paints! CLICK TO SEE FULL PRESENTATION